1. Field of the Invention
The present invention is related to a stand-alone solar energy power generating system, and particularly to a single stage low boost/buck ratio stand-alone solar energy power generating circuit and a system thereof.
2. Brief Description of the Related Art
The typical application of the stand-alone solar energy power generating system is to supply the power for the lighting system. Usually, the energy storage unit, i.e., the battery, stores the solar energy power generated by the power generating unit at the daytime, and the stored solar energy power is supplied to the load unit such as the illumination equipment. Therefore, the typical solar energy power generating system generally includes two-stage converter circuits, a charging converter and a discharging converter.
FIGS. 1 and 2 show the two-stage low boost/buck ratio stand-alone solar energy power generating system in which the Buck converter 11 and the synchronous rectifying Buck converter 21 act as the charging converter circuit, and the Boost converter 12 and the synchronous rectifying Boost converter 22 act as the discharging converter circuit. It can be seen in FIGS. 1 and 2 that the conventional two-stage circuit structure needs many switches and passive elements such that it is incapable of reducing the volume, weight and size thereof. Furthermore, the complication of driving circuit for the respective switch thereof significantly affect the stability of the circuit and it increases the production cost of the circuit.